Preheat broiler. In a bowl stir together panko and paprika.
In a large saucepan cook the next four ingredients (through onion) according to package directions for macaroni, except omit salt; add broccoli the last 3 minutes of cooking. Drain. Return cooked macaroni and vegetables to hot saucepan; keep warm.
Meanwhile, in a medium saucepan whisk together milk, flour, salt, and pepper. Cook and stir over medium heat until slightly thickened and bubbly. Stir in cream cheese and mustard until smooth. Remove from heat. Stir in shredded cheese until melted.
Immediately pour cheese mixture over macaroni mixture; toss gently to coat. Spoon into a 2 1/2- to 3-quart oval baking dish. Sprinkle panko mixture over macaroni mixture. Lightly coat panko mixture with cooking spray. Broil 4 to 6 inches from the heat 1 to 2 minutes or until golden brown.